Situations exist where it desirable to induce specified patterns of displacements, strains, loads or stresses in tissue engineering scaffolding materials, biological cells or substrates to which they are attached, specimens, objects or devices (targets). These include situations where mechanical properties are determined by applying particular loads or combinations of same in specific directions. Other situations include, but are not limited to, manufacturing processes, pre-conditioning of materials, use of stress or strain states to induce fiber alignment, crystallization in the material or to otherwise regulate, alter or transform its properties or structure at the bulk, meso, micro or nano scale, and where such targets are used as a substrate for other materials.
When only a few attachment points are used, the strain pattern in the specimen can be quite different from the intended pattern (for example, a uniform strain field). Using many attachment points can be time consuming, and precise location of those points can be crucial to achieving the desired strain fields. Mechanisms having many levers or similar machinery can provide multiple attachment points that move in synchrony, but they tend to be expensive and complex to design and fabricate.